Class 
Book 







DEPARTMENT OF COMMERCE 

BUREAU OF FISHERIES 

HUGH M. SMITH, Cominis«ion«r 



ARTIFICIAL PROPAGATION OF 
THE SALMONS OF THE PACIFIC COAST 



REVISED AND ENLARGED BY 

HENRY O'MALLEY 

Field Assistant, U. S. Bureau of Fisheries 
In charge of operations on the Pacific coast 



APPENDIX II TO THE REPORT OF THE U. S. COMMISSIONER 

OF Fisheries for 1919 




Bureau of Fisheries Document No. 879 



PRICE, 15 CENTS 

Sold only by the Superintendent of Documents, Government Printing Office 

Washington, D. C. 

washington 
govertWent printing office 

i. 1920 



DEPARTMENT OF COMMERCE 
U BUREAU OF FISHERIES 

HUGH M. SMITH, Commissioner 



ARTIFICIAL PROPAGATION OF 
THE SALMONS OF THE PACIFIC COAST 



REVISED AND ENLARGED BY 

HENRY O'MALLEY 

Field Assistant, U. S. Bureau of Fisheries 
In charge of operations on the Pacific coast 



Appendix ll to the Report of the u. s. commissioner 
OF Fisheries for 1919 




Bureau of Fisheries Document No. 879 



PRICE, 15 CENTS 

Sold only by the Superiutendent of Documents, Govemtnent Printing OfBce 
Washington, D. C. 

VWVSHINGTON 

GOVERNMENT PRINTING OFFICE 

1920 



'' i-^, / 






CONTENTS 



Page. 

The salmons of the Pacific coast 3 

Chinook salmon 4 

Blueback salmon 7 

Humpback salmon 8 

•Silver salmon 9 

Chum salmon 9 

Steelhead 10 

Artificial propagation 10 

Construction of I'acks 11 

Obtaining salmon for propagation 16 

Taking and impregnating the eggs 18 

Hatching apparatus and methods 20 

Packing salmon eggs for shipment 23 

Water supply for hatchery 28 

Care of the fry 28 

Feeding the fry 29 

Planting young salmon 31 

XfJ •f i^* 

jUii 23.1929. 



U. S. B. F.— Doc. 879. 



Plate I. 




ARTIFICIAL PROPAGATION OF THE SALMONS OF 
THE PACIFIC COAST." 



Revised and enlarged by Henry O'Malley, Field Assistant, U. S. Bureau of 
Fisheries, in Cliarge of Operations on the Pacific Coast. 



THE SALMONS OF THE PACIFIC COAST. 

There are fiv^e species of salmon on the Pacific coast belonging to 
the genus Oncorhynchus, namely, the chinook, spring, king, or 
quinnat sahnon ( Onco)-hyncJms tschawytscha) ; the bliieback, sock- 
eye, or redfish {Oncorhynchus nerka) ; the humpback or pink sal- 
mon {Oncorhynchus gorhuscha) ; the silver or coho salmon {Onco- 
rhynchus kisutch) ; and the chum or dog salmon {Oncorhynchus 
keta). Among the features which distinguish the Pacific salmons 
from the Atlantic salmon are the larger number of rays in the anal 
fin and the invariable habit of spawning but once and then dying; 
the xVtlantic salmon may spawn several times. 

The characters noted in the following key will usually be suflS- 
cient to distinguish the different species of Pacific salmon : 

Chinook salmon. — Scales in longitudinal series, about 135; py- 
loric cceca, 110 to 200, averaging 150; gillrakers comparatively short, 
from 20 to 25 in number, 9 being above the angle; rays in anal fin 
from 14: to 19, average 16; branchiostegals, 14 to 19, average 16. 
Body robust; head conic; caudal fin lunate. Color above dusky, 
sometimes with bluish or greenish tinge; sides and belly silvery; 
head dark, with metallic luster, back and sides with prominent spots, 
usually X-shaped. 

Bluehaek salnvon. — Scales in longitudinal series, about 130; py- 
loric cceca, 75 to 100; gillrakers comparatively long and slender, 
from 30 to 40 in number; rays in anal fin, 14 to 18; branchiostegals. 
13 to 15. Body rather slender; caudal fin lunate; anal and dorsal 
fins low. Color, sides silvery, no spots on back, which is frequently 
bright blue. 

Humphack salmon. — Scales very small, 200 or more in longitudinal 
series; pyloric cceca very slender, about 180 in number; gillrakers 
short, from 20 to 25 ; anal rays, 15 j branchiostegals, 11 to 12. Color, 
bluish above, silvery on sides ; lower part of back, adipose fin, and 
tail with numerous black spots, largest and of oblong form on tail. 

Sillier salmon. — Scales large, about 130 in longitudinal series; 
pyloric cceca comparatively few and large, 40 to 110 in number, 

" This paper represents a revision and enlargement of the chapter on " The Salmons 
of the Pacific Coast," from the Manual of Fish-Culture, published in the Report of the 
U. S. Commission of Fish and Fisheries for 1897, a first revised edition of which was 
published separately in 1900. The chapter was subsequentlv issued in separate form 
under the title " Artificial Propagation of the Salmons of the Pacific Coast." 



4 AKTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

average 70; gillrakers long and slender, 20 to 25 in number; anal 
rays, 11 to 15, average 13; branchiostegals, 12 to 14:. Body long; 
head short, conic; snout blunt; eye small; fins small, caudal deeply 
lunate. Color, bluish green, sides silvery, finely punctulated, as in the 
chinook, but not so conspicuous. 

Chum salmon. — Scales of medium size, about 150 in lateral line; 
pyloric cceca, 140 to 185 ; gillrakers from 20 to 25 ; 13 or 14 rays in 
anal fin; branchiostegals, 13 or 14. Form of chinook, but head 
longer and more depressed. Dusky above and on head; paler on 
sides; very fine spots on back and sides, often wanting; tail deeply 
lunate, plain dusky or finely spotted, with black edge; other fins 
blackish. 

These salmons are the most important group of fishes entering the 
rivers of North America. The steelhead {Salmo gairdneri), popu- 
larly regarded as a salmon, also inhabits the waters of the Pacific 
coast and adds to the importance of the salmon tribe. 

In recent years the annual catch of salmon in the Pacific Coast 
States, British Columbia, and Alaska has been approximately 
585,000,000 pounds, with a value, as placed on the market, of nearly 
$40,000,000. In 1918 the quantity of salmon canned was 7,829,212 
cases of forty-eight 1-pound cans. 

CHINOOK SALMON. 

The chinook salmon {Oncorhynchus tschawytscha) is also known 
by other names than those given above, as Columbia, Sacramento, 
and tyee salmon. It is one of the most important of the salmons, 
being superior in food qualities and attaining a vastly larger size 
than any of the others. When fresh from the ocean, it is a very 
handsome, resplendent, well-formed fish. The flesh is of a rich red 
color in the greater number of individuals, but all runs contain a 
smaller or larger percentage of fish having white meat. Buyers cut 
into the shoulder of the fish for arriving at the color. The white 
meat is equally as good as the red as a food, but the rich red fish 
have the greater market value, both in .the fresh condition and for 
canning. 

No other salmon in the world compares in size with the chinook. 
In the Yukon Kiver, Alaska, it occasionally attains a weight of 
over 100 pounds; and in the Columbia Kiver there have been well- 
authenticated cases of specimens weighing over 80 pounds. Far- 
ther south the size is smaller, although in the Sacramento Kiver indi- 
viduals from 50 to 60 pounds in weight are not rare. In the Columbia 
20 pounds is a fair average, and in the Sacramento about 16 pounds. 

The known range of the chinook in American waters is practically 
from Monterey Bay (latitude 36^°) to the Yukon Kiver, but indi- 
viduals have been seen in Norton Sound, somewhat north of the 
Yukon, and as far down the coast of California as the Santa Bar- 
bara Channel. However, it is not known to spawn naturally in 
any stream south of the Sacramento Kiver. It extends across Bermg 
Sea to Kamchatka and south to Hokkaido, Japan. 

Fish of this species prefer the larger rivers, like the Sacramento, 
Columbia, Skagit, Nushagak, and Yukon, and they are very per- 
sistent in making the ascent. The summer and later runs seek 
spawning grounds not far from the ocean, but the first or early 



ARTIFICIAL, PROPAGATION OF PACIFIC SALMONS. 5 

spring runs ascend to extreme headwateri?; They have been seen 
crowding up rivulets forming the headwaters of the Sacramento 
and Cohnnbia Rivers with nearly half their bodies exposed above 
water. No matter how far the headwaters are from the ocean, some 
of the run will proceed till forced to yield to an impassable obstruc- 
tion. On reaching their goal the early fish remain several weeks in 
deep, quiet holes before going on the spawning grounds. The rate 
of ascent varies with climatic conditions, the season, and the condi- 
tion of the rivers, which are affected by melting snow during the 
spring and summer and by rains in the fall months. They proceed 
very slowly at low-water stage, sometimes l3'ing for weeks or months 
in deep pools, and rapidly when the water is at a moderate stage ; but 
at extreme high or flood stage they remain quiet until the water 
begins to fall and clears, when they resume their journey. 

When they first come from the ocean the sexes are very similar in 
appearance, but as the time for spawning approaches a difference is 
noted between them, becoming more pronounced as the season ad- 
vances. The developing ova of the female produces a round, plump 
form, while the male becomes thin, his head flattening, and his upper 
jaw curving like a hook over the lower. His eyes sink; large, power- 
ful, white, doglike teeth appear on both jaws; and the fish acquires 
a gaunt and savage appearance. From the time they reach fresh 
water their appetites decrease, and their throats and stomachs gradu- 
ally shrink, until, at the near approach of the spawning season, they 
have become entirely incapacitated for food, and the desire and the 
ability to feed has left them entirety. The great reserve of flesh and 
oils brought with them from the ocean enables them to keep the vital 
organs active until their mission is accomplished. After reproduc- 
tion they die on or near the spawning grounds. This singular fact 
has been disputed, but its truth has been proved conclusively and re- 
peatedly. After they are entirely spawned out they remain on the 
beds, deteriorating rapidly, the flesh shading off to a light, dirty pink, 
and they become foul, diseased, and much emaciated. Their scales 
are partly absorbed and, in the males, wholly enveloped in the skin, 
which is of a dark-olive or black hue ; blotches of fungus appear on 
their heads and bodies; and in various places there are long, white 
patches where the skin has been partly worn off. Their tails and fins 
become badly mutilated, and in a short time the fish die. 

They are found feeding in Monterey Bay in any month of the 
year when food is there. On their way to the spawning beds they 
reach this body of water about the second week in January and may 
be caught with hook and line. In February they may be observed 
in numbers in the Sacramento River. In the Columbia River they 
appear in March but are not abundant until April or May. They 
arrive in southern Alaska in May and farther north in June, while 
it is probably still later before they ascend the Yukon, where the 
running season is short and may not exceed a month or six weeks. 
The early runs in the Columbia River are usually from one to three 
weeks in passing from the mouth of the river to Clifton, a distance 
of about 20 miles. They first arrive at The Dalles, 200 miles up the 
river, in the middle of April, and are found in numbers at this 
point about the middle of June, two months after appearing in 
larger numbers at the river bay, thus covering a distance of about 



b ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

100 miles a month. As the season advances the rate of progi-ess up 
the rivers is more rapid. 

The spawning season varies in different rivers and covers a period 
of at least four months. The spring run begins to spawn at the head- 
waters of the Willamette and Salmon Rivers, tributaries of the 
Columbia, in August, while the summer run at the Little White 
Salmon and Big White Salmon stations, nearer the ocean, be^ns 
spawning about September 20. At the Clackamas (Oreg.) station, 
eggs are secured from the fall run from the last of September to 
about December 1. 

For the deposition of their eggs chinook salmon invariably seek 
a shallow, gravelly riffle, where the water is a foot or more deep, 
and the current sufficiently swift to carry and spread the eggs and 
milt. There is no doubt that in many instances the so-called nest, 
which is an elongated cavity or depression, often several feet across 
and 12 or more inches in depth, is started by either the male or female 
in advance of actual spawning, but as a general thing it is formed 
by the fish in the act of spawning. At this time both the male and 
female turn on their sides and by contraction of the abdominal 
muscles, which produces a (juivery motion of the body, effect the 
simultaneous emission of milt and eggs. At about the same time 
a forceful movement of the tail and posterior part of the body serves 
to loosen the gravel and propel the fin forward more or less, thus, by 
frequent repetition, enlarging the depression and covering tlie eggs 
with the loose gravel. It seems evident that this is nature's provision 
for the protection of the eggs, during the incubation period. With 
every effort made by the fish in the extrusion of the eggs and milt 
the depth of the covering is increased, and this serves not only to 
screen thorn from the light, which is conducive to the growth of 
fungus, but also protects them from the prying eyes of trout and 
other active aquatic enemies. 

The length of time consumed in spawning is largely governed by 
the number of eggs a female contains and also by the temperature of 
the water. In solne instances all of the eggs will be deposited within 
a day or two, while in others spawning will extend over a period 
of a week or 10 days. 

Both the eggs and the fry are subject to destruction by freshets 
washing them out of the gravel or covering them so deep that, if they 
are not actually killed by the pressure on them, it becomes impossible 
for the fry to work their way out. In many streams spawning occurs 
during high-water stages in the fall, the eggs in numerous instances 
being deposited in gravel which is entirely above the water later in 
the season. Many eggs are lost also by trout lying close in behind 
the salmon and catching them as they are emitted. Some are rooted 
out of the nest, and the natural enemies take their toll as the fry 
emerge from the gravel. It is the instinct of the fry to lie quiescent 
until the umbilical sacs have been absorbed, when they leave the nest 
in search of food. 

Experiments conducted some years ago by John P. Babcock <^ have 
demonstrated clearly that only those eggs in natural spawning which 
are embedded beneath from 5 to 6 inches of sand and gravel produce 



" Some experiments in the burial of salmon eggs, suggesting a new method of hatching 
salmon and trout. Transactions, American Fisheries Society for 1910, pp. 393-395, 
Washington, 1911. 



U. S. B. F.— Doc. 879. 



Plate 1 1. 




FIG. I.-CHINOOK SALMON. BREEDING MALE 




FIG. 2.-BLUEBACK SALMON. ADULT MALE. 




FIG. 3. -HUMPBACK SALMON. ADULT MA 



LE. 



U. S. B. F.— Doc. 879. 



PLATE III. 




FIG. I.-SILVER SALMON. BREEDING MALE. 




FIG. 2.— CHUM SALMON. BREEDING MALE. 




^ ^p i .^ji ii p^i ii pCi, 




FIG. 3— STEELHEAD. 



ARTIFICIAL PEOPAGATIOX OF PACIFIC SALMONS. 7 

alevins that live to attain the fry stage, and that the eggs not so 
covered are either consumed by active natural enemies or are de- 
stroyed by the vegetable mold known as fungus. The experiments 
have shown that the burial of freshly fertilized eggs of Pacific 
salmon in sand or gravel to the depth stated does not smother them, 
but that eggs so treated will hatch, and the resulting alevins will 
possess the instinct and power to work their way gi-adually to the 
surface after the disappearance of the food sacs, at which stage of 
development they are not attacked by fungus. Eggs buried imder 
from 2 to 3 inches of gravel were found to produce alevins coming 
to the surface before the sacs had been absorbed, and they were 
therefore subject to fungus, a very large percentage of them being 
destroyed in that way, as well as by the more-developed forms of 
aquatic life. The sacs of fry resulting from eggs buried less than 4 
inches deep are so thinly covered when they reach the surface that 
few, if any, of the fish survive the effects of fungoid growths, and, as 
such growths are very common in the beds of streams where large 
numbers of salmon have spawned and died, it follows that very 
heavy losses of eggs must occur on eggs naturally deposited. 

The yield of eggs from the chinook salmon will average from 3,000 
to 6,000 per fish. The eggs are of a deep, salmon-red color, measur- 
ing about one-fourth of an inch in diameter, and are heavier than 
water. 

In view of the enormous annual catch of this salmon for com- 
mercial purposes, the necessity for its propagation became mani- 
fest at an early period in the history of the Pacific fisheries. For- 
tunately, it is readily susceptible of artificial production on a large 
scale; otherwise the supply in western rivers would by this time 
have materially fallen off. Since the work began in 1873 on the 
McCloud Eiver it has grown to larger proportions. It now engages 
the attention of all the coast State governments, as well as that of 
the Federal Government, and the work is steadily growing in im- 
portance. 

As the salmon ascend the rivers they are caught by gill nets, fyk& 
nets, pounds, weirs, seines, wheels, and other devices, but in the 
Sacramento and Columbia Elvers the greater numbers are caught 
as they head upstream with gill nets drifting with the current or 
tide. In the rivers they are comparatively safe from enemies, but 
immense numbers are destroyed at the mouths of the streams by seals 
and sea lions. 

This species has been introduced into Australia, New Zealand, and 
Europe, but so far as is known New Zealand is the only country 
where its acclimatization has been effected. Efforts have been made 
to establish it in Atlantic streams of the United States, but with- 
out permanent results. In some of the fresh-water lakes of New 
England the chinook salmon has been introduced purely for angling 
purposes. In such instances permanent fisheries can not be ex- 
pected save by restocking. 

BLUEBACK SALMON. 

This species {OncorJiynchus nerha) is known in different regions 
under the names of blueback, redfish. Eraser Eiver salmon, and sock- 
eye. It ranks first of the salmon in commercial value, being es- 



8 AETIFICIAL PROPAGATION OF PACIFIC SALMONS. 

pecially important in the Fraser River and in Alaska. The color of 
the flesh is a rich red, which persists after canning. Large quanti- 
ties are canned on Puget Sound, in British Columbia, and in Alaska, 
and its commercial value to that territory is indicated by the fact 
that during the calendar year 1916 the total pack on the Pacific 
coast amounted to 2,432,048 cases. Of this total 2,119,442 cases were 
put up in Alaska, at a valuation of $13,147,994. Comparatively few 
red salmon are sold fresh in the United States. 

It is next to the smallest of the salmons, the maximum weight 
being 12 pounds, but it seldom attains a weight of over 6 pounds in 
any instance.*^ 

It ranges from Columbia Eiver, Wash., to the far north. In gen- 
eral it ascends only such rivers as rise in glacial and snow-fed lakes. 
Practically nothing is known of its ocean life. Straggling speci- 
mens occur in the Quinault River late in December. It ascends the 
Columbia River in June and July, and at Kocliak Island it comes 
in numbers in June. There the heaviest run is in June and July, 
spawning occurring in August and September. In the Fraser River 
the largest runs enter during July and August, and in the water- 
shed of this river spawning occurs from late October to the end of 
December, being at its maximum during November. Quinault and 
Baker Lakes, together with their tributaries, may be considered 
typical spawning grounds for this fish in the United States, and in 
those regions the spawning season extends from early September to 
late December. 

The individuals of this species enter only such streams as have 
lakes at their headwaters, usually reaching the vicinity of the latter 
several weeks in advance of spawning time. Many of them deposit 
their eggs along the lake shores in depths of from 1 to 12 feet of 
water. Others ascend the creeks or rivers flowing into the lakes and 
spawn on the riffles in a way similar to that of the chinook salmon. 
The average number of eggs per fish ranges from 2,500 to 3,000. 
Except in the breeding season, the color is a clear, bright blue above, 
with silvery sides and belly. At spawning time the body becomes 
blood red and the head light green. The male loses his symmetrical 
form and develops an extravagantly hooked jaw. 

HUMPBACK SALMON. 

The humpback salmon {Oncorhynchus gorbiischa) is the smallest 
of the Pacific salmons, its average weight being only 5 pounds and 
its maximum rarely 9. Its range is from Puget Sound northward, 
probably as far as the Mackenzie River, and it is also common on 
the Asiatic coast. The southernmost spawning record is in the San 
Lorenzo River at Santa Cruz, Calif. In Alaska it is the most abun- 
dant and generally distributed of the salmons, and in that region 
there is an annual run of the species. In Puget Sound waters, how- 
ever, it makes its appearance in numbers only in alternate years. No 
satisfactory explanation as to the cause of this phenomenon has been 

« So-callod landlocked forms occurring in various lakes weigh only one-half pound 
when mature. They are commonly referred to as little redfish and have long been re- 
garded as merely dwarfed forms of the anadromous species. At one time they were be- 
lieved to ascend also from the sea ; later it was conclusively proved that they are perma- 
nent residents of fresh water, and there is strong evidence that they constitute one or 
more distinct species. 



ARTIFICIAL. PROPAGATION" OF PACIFIC SALMONS. 9 

given. During the fall of 1916, which is known as the off season in 
Puget Sound, 1,887 cases were packed. This shows a healthful in- 
crease over the seasons previous to the Bureau's attempting the estab- 
lishment of an annual run in this region. 

In nutritive value the fresh-run humpback is scarcely inferior to 
any other salmon. While the flesh has a very fine flavor, it is 
paler than that of the chinook or blueback salmon, and it loses its 
color when canned. The total amount of this species canned during 
the calendar year 1916 was 2,036,077 cases, of which amount 1,753,546 
cases, valued at $6,446,168, were packed in Alaska. 

The humpback salmon usually seeks the smaller streams for repro- 
duction, dej:)ositing its eggs a short distance from the sea, sometimes 
within a few rods of the ocean. At Kodiak Island, Alaska, where 
it is often very abundant, it arrives in the latter part of July, the 
run continuing only a few weeks. Spawning occurs in August. The 
eggs, of which there are about 2,000 per fish, are smaller than those 
of the chinook, but larger than those of the blueback and paler than 
either. 

Shortly after its arrival from the ocean, and with the approach 
of the spawning season, it develops on its back a prominent hump, 
which, with the distortion of the jaw, gives the fish a very singular 
appearance. As is the case with the other salmons, it dies on the 
spawning bed or after being swept to sea by the current. 

SILVER SALMON. 

The silver salmon {Oncorhynchus kisvfch) is also known as silver- 
sides and coho salmon. It is a beautiful fish, having a graceful form 
and a bright, silvery skin. Its flesh is usually of a bright-red color; 
but, as this fades on cooking, it is less highly regarded for canning, 
though large quantities are thus utilized on the Columbia River, 
Puget Sound, and the short coastal streams of Oregon and Wash- 
ington. 

In 1916 the total pack was 715,815 cases, of which 265,184 were 
put up in Alaska. Its range is from Monterey Bay to northern 
Alaska, and as far south on the Asiatic coast as Japan. It ascends 
the rivers to spawn in the fall and early winter, when the waters 
are high. In most of the rivers which it frequents there appear to 
be two well-defined runs, the early run ascending to the headwaters, 
while the later run is found in the streams nearer the ocean. The 
early run is composed of small-sized specimens. In Alaska the aver- 
age weight of this salmon is nearly 15 pounds, and in the streams far- 
ther south about 8 pounds. It rarely attains a weight of 30 pounds. 
The average egg production per fish is about 3,500. 

CHUM SALMON. 

The chum salmon {Oncorhynchus keta) is the least valuable of the 
Pacific salmons, although it is canned and dried in large quantities 
on the Pacific coast and in Alaska. Its average weight is 10 pounds, 
and the maximum is about 20 pounds. It is found from the Colum- 
bia River northward, being especially abundant in Alaska. It is 
taken occasionally in the Sacramento River. When just from the 
ocean, the flesh is of a very pale red color. At that time it is a very 
138982°— 20 2 



10 ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

good fish, but it deteriorates rapidly in fresh water, and it loses its 
color in the can. It spawns in shallow riffles and creeks, usually at 
no great distance from the ocean. Large quantities are packed in 
Oregon, Washington, and Alaska. The production of canned chum 
salmon in 1916 amounted to 1,500,332 cases, of which 715,238 cases 
were put up in Alaska. 

STEELHEAD. 

Another anadromous fish found in Pacific coast waters is the steel- 
head {Sahno gairdneri), commonly known as steelhead and steel- 
head trout, and in many instances erroneously classed with the 
Pacific salmon in the State laws. It resembles in form, size, and some- 
what in general appearance the salmon of the Atlantic coast, but is 
distinguished from the Pacific salmons by its short anal fin of not 
over 12, and usually 9 or 10, rays, square tail, small head, rounded 
snout, comparatively slender form, light-colored flesh, and its spring- 
spawning habit. Its average weight in the Columbia is about 12 
pounds, but specimens weighing 42 pounds have been found in the 
Skagit Kiver. 

Its range is very extended, reaching from Santa Barbara on the 
southern coast of California to the Alaskan Peninsula, and perhaps 
to the Arctic Ocean. It is found in almost all the streams of the 
Pacific States which empty into the ocean. The only run of this 
species of commercial importance in the Columbia River begins in 
late June and is in full force in July and early August. It reaches 
Seufert, Oreg., about the close of the blueback run, and some of the 
fishing wheels catch practically nothing else. This fish feeds while 
in fresh water, and does not always die after spawning, but it de- 
teriorates from the time it enters fresh water until the following 
spring, and spawns between the months of February and May. Its 
movements in other rivers on the coast are not materially different, 
except that it enters the southern rivers earlier and the northern 
rivers later than it enters the Columbia. Like the chinook salmon, the 
steelhead ascends for long distances, and it has been found as far up 
tributaries of the Columbia as the ascent of fish is possible. The 
number of eggs per fish ranges from 6,000 to 8,000. The greater quan- 
tities of steelhead trout are caught during the winter and spring 
months and are utilized in a fresh state, large quantities being 
shipped to eastern markets in refrigerator cars. However, during 
the calendar year of 1916 cases of this species to the number of 
24,999 were packed. 

ARTIFICIAL PROPAGATION. 

Artificial propagation having been first applied on the Pacific 
coast to the chinook salmon, the description of methods which follow 
is based mainly upon the practices employed with that species. In 
1916 the number of salmon and steelhead eggs collected by the 
Bureau of Fisheries, expressed in millions, was as follows : Chinook, 
108; blueback, 105; humpback, 32; silver, 13; chum, 29; steelhead, 
14. These were collected at the Afognak and Yes Bay stations in 
Alaska; at stations located on tributaries of Puget Sound and in 
the Quinault Indian Reservation, Wash.; at Clackamas and its aux- 
iliaries in the Columbia River Basin and in southern Oregon; and 



U. S. B. F.— Doc. 879. 



PLATE IV. 




FIG. 1.— SALMON HATCHERY, AFOGNAK, ALASKA. 




FIG. 2.— SALMON HATCHERY AND REARING PONDS, YES BAY, ALASKA. 



U. S. B. F.— Doc. 879. 



PLATE V. 










1 * »*> 



FIG. 1.— ROGUE RIVER (OREG.) HATCHERY. 




FIG. 2.— CLACKAMAS (OREG.) HATCHERY. 




FIG. 3.— BIRDSVIEW (WASH.) HATCHERY, 



AETIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



11 



at the California stations on tributaries of the Sacramento and 
Klamath Eivers. In addition, the j^rivate hatcheries operated by 
the salmon-cannery interests of Alaska, known as Fortmann, Kar- 
Ink, Quadra, Hetta, and Klawak, which have been hatching blue- 
back salmon for years, collected in 1916 over 87,000,000 eggs. The 
normal capacity of these five establishments is 197,000,000 eggs per 
annum. The Bureau's two hatcheries in Alaska have each a capacity 
of 72,000,000 eggs. 

CONSTRUCTION OF RACKS. 

The eggs found in salmon that are captured for connnercial pur- 
poses are in a green state, and, therefore, in all hatchery operations 
of importance it has been found necessary to provide for the egg 
supply by installing requisite devices for the capture and retention 




Fig. 1. — Three-legged rack horse or trestle : A., horse head ; B.B., horse legs ; G.G.G., 

12-inch boards to make sides of crib and also to act as braces ; D.D.D., leg braces 

which also support bottom of crib; E.E.E., bottom of crib; X.X.. bracket for support- 
ing walk. 

of the brood fish. Such fishing is conducted at or near the spawn- 
ing grounds. 

The site selected for the placing of the racks should be in a good 
spawning locality. The upper rack is placed at the head of a riffle, 
and the stop or lower rack is installed just below a deep pool, the 
distance between the two depending upon topographical conditions. 
There is thus provided between the upper and lower racks a proper 
spawning and fishing area, Avith a deep pool for a resting place for 
the immature fish. In this inclosure the fish are held until removed 
for stripping. The racks are designed to control the movements of 
the fish regardless of the water stages, as failure to do so means the 
loss of a season's take of eggs. 

The usual form of rack constructed in the rivers of Washington 
and Oregon and in most of the streams in California is built on 
trestles or three-legged horses, their sizes depending upon the char- 
acter of the streams to be closed, and their length upon the depth 
of water and the angle or slope to be given the rack. The legs are 
made of pile timber from 8 to 12 inches in diameter. The upper leg 



12 ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

is longer than the other two, which are of equal dimensions, and is 
attached to them at an angle of 90°, the spread between the others 
being about 60°. The legs are braced and held in place by poles 
about 4 inches in diameter, which are spiked to the sides midway 
from the ground to where the legs are joined, and, as an extra pre- 
caution, an additional brace is nailed across the two rear legs. 

The braces strengthen the bottom of the crib, which is made of 
1-inch rough lumber, and the 12-inch boards composing its sides 
serve as an additional brace to the legs. Such a crib will hold from 
100 pounds to almost a ton of rock, the amount varying with the 
size of the braces used and the current which it is expected to with- 
stand. 

The trestles are set from 8 to 12 feet apart directly across the 
stream on the site selected for the rack, the distance between each 
being governed by the size of the stream and the strength of rack 
desired. The trestles are then lined up and loaded with stones, and 
two stringers from 8 to 12 inches in diameter are put on and spiked 
to the upstream side of the forward leg. While the position of the 
stringers must be governed to some extent by the height of the rack, 
it is usual where the rack is of ordinary construction to place the 
upper stringer about 30 inches above the water surface and the 
lower one midway between that point and the river bottom. 'On 
large streams a third stringer is sometimes used to good advantage. 

Where the bed of the stream is of hard formation 2 by 3 fir pickets 
are put down even with the bottom at intervals of 1^ inches and 
nailed to the stringers, the 2-inch surface being placed to the current 
and the upstream edge beveled in order to present the least possible 
resistance to the current. In streams with soft shifting bottoms it 
is often necessary to drive the pickets. As a further precaution 
against the escape of the salmon by the loosening and displacement 
of the pickets by the current, or by the struggling of the fish, a 
block 3 inches long by 1^ inches wide is nailed to each picket at a 
point halfway between the lower stringer and the bottom. A layer 
of bowlders and rock from 3 to 5 inches in diameter is then placed 
in front of the rack at the point of the pickets to close effectually all 
openings betw^een the ends of the pickets and the river bottom; and 
brackets for supporting a walk are nailed to the downstream side 
of the trestles, thus providing a means of keeping the rack cleared of 
debris at all times. 

In streams where shingle bolts, cordwood, and driftwood occur, a 
gate is provided for their passage, and the necessary sheer booms are 
constructed in front of the racks to guide the timbers to the opening. 
The gate should be built between two trestles which have been placed 
8 feet apart, and the open space comiected by a stringer placed below 
the surface of the water at a depth of at least 18 inches. Pickets are 
attached to this stringer in the usual manner, except that they must 
be sawed off even with its top, and the sides of the space are squared 
up and walled with 1-inch lumber. 

The gate is constructed of 1 by 4 inch strips 12 or more feet long, 
which are placed on edge at intervals of 1^ inches, well blocked and 
braced. It is then hinged to the stringers in such a manner that it 
will swing freely. One way to accomplish this is to bore holes 
through the ends of the strips and insert 1-inch pipe, the ends of 
which, projecting a few inches on either side of the gate, allow it to 



ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 



13 




14 



AKTIFICIAL PROPAGATION OF PACIFIC SALMONS. 




turn in eyebolts in the side walls. To pre- 
vent the fish passing through when the gate 
is open, a 12-inch board should be nailed 
across its under side at such an angle that 
the current rushing against it will lift the 
lower end of the gate just above the surface 
of the water. Floating objects coming 
down the stream are carried onto the gate, 
which sinks from their weight, and as the 
current carries the object on the gate closes 
automatically. 

Racks constructed in accordance with 
this method will often stand submerging 
several times in the course of a spawning 
season, and at its close remain practically 
undamaged. 

A barrier that has stood the test of sev- 
eral years and has proved that it will oper- 
ate successfully in almost any stage of 
water is described in the following para- 
graphs.« The design is to be credited to 
A. H. Dinsmore, former superintendent of 
the Baker Lake (Wash.) station. 

A permanent barrier at the Birdsview station, 
an auxiliary of the Balder Lake station in Wash- 
ington, is of novel construction and calls for 
more than passing notice. This barrier is located 
in a portion of Phinney Creek, where formerly 
there was a dam built for the pui'pose of obstruct- 
ing the passage of steelhead trout. When the 
dam washed out, a new channel formed and the 
river bed was very much broadened. 

The first step in the construction of the new 
barrier was the laying of four heavy log stringers 
across this new channel from the abutment on the 
north to the new bank on the south side of the 
stream. The logs were let down through the dam 
foundation to low-water level on the north side, 
and the deep channel under them on the south side 
was filled with brush and gravel. The logs were 
spotted down to form a practically level bed, 
reaching the width of the stream. Heavy piles 
were then driven behind each stringer to form 
alternate single and double rows extending up and 
down stream. The log stringers were next 
planked over, forming a platform 18 feet wide, 
similar to a regular dam apron, extending from 
the north abutment to the final row of piles on the 
south side, a distance of about 140 feet. 

By planking the sides of the single row of piles 
and all around the double rows and filling the 
space with rocks, piers 4 feet high and approxi- 
mately 2 feet and 4 feet wide were formed. 
Through each pier at the bottom, behind the 
upstream pile, openings 1 foot square were left, 

" Titcomb. .John W. : Fish-cultural practices in the 
Bureau of Fisheries. Bulletin, U. S. Bureau of Fish- 
cries, Vol. XXVIII, for 1008, part 2, pp. 728-732. 
Washington, 1910. 



ARTIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



15 



connecting the spaces between the piers. These spaces, 12 in number, are 
approximately 8 feet wide and are filled by swinging gates hinged to a 3 by 12 
inch timber, spiked securely to the piers on either side and forming a dam or 
flashboard across the space above. By the insertion of other flashboards above 
this one a tight dam 4 feet high can be quickly formed at any time. The 
utility of this feature will be explained elsewhere. 

The gates are made of 1 by 4 inch fir set on edge and nailed to 2 by 4 inch 
joists, being strengthened by 2-inch blocks set between the rack bars and nailed 
to them and the joists. These blocks thus determine the width of the inter- 
stices in the gates. At the upper end of each gate an auger hole is bored 
through the bars and blocks, to accommodate a 2-inch iron pipe, which passes 
through the entire upper end of the gates. Ringbolts clasp these pipes and are 
fastened to the 3 by 12 inch timber forming the flashboard, acting as hinges 
upon which the gates swing. At the lower end of each gate a wide board, li by 
16 inches, is secured by means of braces, forming an angle of 45° with tlie 
lower end of the gate. 

At an ordinary stage of the stream the do\^Tistream ends of the gates rest on 
supports which hold them a foot or more higher than the upper ends, the water 
passing down through them to the floor of the apron, where it runs away. The 
fish working up under the gates to the dam board find the cross passages 
through the front end of the piers and finally reach the trap. It was expected 
that during freshets the cun-ent acting on the flashboard would always keep 
the lower ends of the gates above the surface of the water, and up to a certain 




Fig. 4. — Side elevation of barricade shown in figures 2 and 



point this expectation was realized, but at very high stages of the stream the 
large quantity of gravel in the water soon clogs and sinks the gates. As the 
gates are only two-thirds the length of the apron, however, and rise toward the 
lower end, the water shoots over them with such force that it is projected .some 
distance below the end of the apron, and fish attempting to scale the obstruction 
fall far short of the ends of the gates. The barrier has been watched many 
times when fish were jumping and when the largest drift ran clear, and none 
has ever been seen to pass it. 

P>y means of the dam boards entire control of the current can be had during 
ordinary stages of water and any desired quantity sent to any section of the 
barrier. Thus a strong current can be maintained through the trap section, 
leading the fish to it, and when it is desired to remove the fish from the trap 
the water can practically all be turned to some other section of the barrier. 

One of the greatest difficulties in maintaining traps in the streams in this 
section is due to the tremendous quantities of gravel carried in the water 
during freshets, a sufhcient amount being frequently deposited in front of a 
trap at such times to change the course of the stream. With the present 
form of barrier no trouble is experienced from this source, the insertion of the 
dam boards and the opening of one space at a time quickly clearing away the 
accumulated gravel. 

The ninth and tenth piers were continued upstream by driving three ad- 
ditional piles above each. The piers form the sides of the trap. Its floor is a 
plank bottom, similar in construction to the apron, and the front is barred by 
If-inch pickets placed If inches apart, the fish entering by the usual upstream 
V of pickets. To protect the trap from high water the two piers between 
which it is located were carried "to a height of 8 feet. When it is desired to 
fish the trap, the gate at its head is closed and entrance is made from below 
by means of a door in the north side of the V. 



16 



AETIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



The upper end of the fishway of the old dam was left in place, the nari'ow 
passage between it and the new trap protecting the spaces at the south end of 
the barrier from the current and from drift. These spaces have been racked 
above and below to form commodious pens for males and unripe females. The 

south end of the barrier 
is protected by a substan- 
tial abutment. 

The maintenance of the 
racks in Phinney Creek 
has been a very heavy 
item of expense in past 
years, and the trap was 
frequently carried away 
by freshets just at the 
height of the season, al- 
lowing large numbers of 
fish to escape and con- 
siderably reducing the 
season's take of eggs. 

Concrete piers have 
been used in some of 
the California rivers, 
but they are now con- 
sidered too expensive 
for fish-cultural work 
on an economical scale. 
In some of the streams 
in that State piles are 
substituted for trestles. 
These are sawed at the 
proper angle, capped 
with timbers of the 
right size, and used 
for supporting the 
rack stringers. In con- 
structing racks' in this 
way the pickets are 
usually placed in sec- 
tions and hoisted into 
position by means of a 
derrick. Mudsills are 
embedded in the gravel 
beneath the rack and 
a floor placed thereon. 

OBTAINING SALMON FOR 
PROPAGATION. 

The manner of cap- 
turing the brood fish 
varies in accordance 
with the nature of the 
stream where the work 
is conducted. On some rivers the upstream trap is successfully used 
in connection with the head rack (PI. 1). The tray used is sometimes 
a square or oblong inclosure; at other times it is a pen constructed 
of lumber. In either case the entrance is made on the principle of 




U. S. B. F.— Doc. 879. 



PLATE VI. 




AKTIFICIAL PROPAGATION OF PACIFIC SALMONS. 17 

the ordinary pound net. In their eager efforts to pass upstream 
the fish go 'through the V-shaped mouth of the tfap, and, having 
once entered, they seldom find their way out. The trap is usually 
covered to prevent the escape of the fish by jumping. 

In streams where the current is strong, as in Oregon and Wash- 
ington, the fish are sometimes taken on the riffles by means of gill 
nets; but, as many are killed or injured when so caught, this method 
should be employed only as a last resort. 

In the comparatively slow streams of California it is customary 
to employ drag or sweep seines of suitable length and depth, which 
are operated below the head rack and above the retaining rack. 

Where the natural conditions will permit, the most economical 
means of capturing salmon is by the use of a downstream trap. The 
use of this device necessitates that the upper rack be placed across 
the river at the head of a spawning riffle having a good fall. The 
wings of the trap, constructed on the same principle as the rack and 
with openings provided near the shore ends for the entrance of the 
salmon to the spawning waters below the main rack, are run down- 
stream from one or both shores, as local conditions may require, and 
at their convergence the trap is located. The trap, which is usually 
about 5 feet wide, is made of smoothly dressed slats or poles, the 
small ends of which are nailed to a light sill sunk in the bed of the 
stream, with a space of 1^ inches between each pole, to allow the 
water to flow through freely. From the sill they rise in a gentle 
incline downstream to a level a few inches above the point where 
the water runs through, and they are then sprung down and nailed 
to sills, forming the bottom of the trap. The sides of the entrance 
and the trap proper are usually made of poles or pickets placed 
horizontally, with sufficient space between to permit water to escape 
freely. The sides of the entrance are well braced to withstand the 
pounding of the salmon when rushing into the trap in numbers, and 
on either side of the trap live pens for holding the ripe fish are 
constructed. Across its entrance a grating is placed to prevent the 
fish from being carried into it when not in use. 

When the trap is to be fished, the openings in the lead are closed 
and the grating at the entrance removed. The seine is laid out at the 
head of the riffle, whence it is rapidly carried by the current down- 
stream toward the trap. The fish on the riffle become frightened at 
the seine and run downstream. Following the converging leads and 
traveling rapidly with the current, they are driven into the mouth 
of the trap. Before they can turn, their momentum carries them 
high and dry onto the trap floor, where an attendant picks them up, 
liberates the green fish in the water below, and places the ripe males 
and females in their respective pens. The fish which try to turn 
back before reaching the trap are caught by the heavy leaded seine 
and held against the lead racks until the fishermen find them. 

At the Big White Salmon station of the Bureau of Fisheries suc- 
cess has been attained by purchasing salmon from the fish-trap men 
and towing them in live cars to an inclosure made by racking a 
spring creek having a soft, sandy bottom, which is particularly 
adapted to the successful ripening of immature fish. The death rate 
of the fish while being held there to ripen is small, and the eggs 
taken from them are of excellent quality. 



18 ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

At Baker Lake the fish are taken in a web trap as they enter the 
lake and are impounded in a slough at the head of the lake and held 
there successfully for several months. When mature, they are re- 
moved from the inclosure by means of a drag seine. 

Wliere immature salmon are to be held for any length of time, an 
inclosure with a soft, muddy bottom should be provided for the pur- 
pose, it having been found by experience to be far superior to a 
gravel bottom. 

A rather novel method is employed for capturing silver salmon 
and steelheads where the barrier preventing the ascent of the fish 
chances to be a dam or a natural fall. At an advantageous point, 
where the water pours over the crest of the barrier and where the 
fish are known to jump in their attempt to ascend the river, a device 
known as a jumping box is installed, being placed back of the fall 
at a sufficient height, so that when the fish jump they will be likely 
to fall through the water into it. The length of this box or trough 
is governed by local conditions; its width varies from 18 to 21 inches, 
and it is given a fall of at least 12 inches to each 10 feet of length. 
A covered flume with a sharp fall connects it with a live box, which 
is placed in the stream in such a manner as to insure its protection 
so far as possible from high water, and fvt the outlet of the flume 
leading to the live pen a downstream V is placed. This, together with 
a secure cover, serves to prevent the escape of the fish from the pen. 

In the operation of this contrivance the fish fall into the jumping 
box, and before they can regain their equilibrium they are carried 
into the live pen and are held there until removed. Care must be 
taken to prevent overcrowding in the pen, as, when the fish are jump- 
ing from 6 to 9 a. m. and from 3 in the afternoon until sundown, 
they are apt to be taken in such numbers that loss from smothering 
will result, unless the pen is emptied at frequent intervals. 

TAKING AND IMPKEGNATING THE EGGS. 

When chinook-salmon eggs are taken on a large scale, say from 
a half million to three or four millions per day, as is customary at 
the Little Wliite Salmon station on the Columbia Kiver, spawning 
usually occurs daily throughout the egg-collecting season, it being 
impracticable to hold the fish in pens for any length of time, as they 
injure themselves more or less in fighting against confinement, and 
many eggs are dropped. 

The females are placed in pens by experienced men, and ripe 
ones only are put in. Of the signs that indicate ripeness in a female 
salmon the separation of the eggs in the ovaries is the surest. Spe- 
cific signs are all fallible, however, and the spawn taker must rely 
mainly on an indescribable ripe look, which is neither color, shape, 
nor condition of organs, but a general appearance which shows at 
a glance that the fish is ripe. This knowledge can be gained only by 
experience. 

An attendant gets into the pen containing the females and catches 
a fish by the tail with his left hand, on which is worn a woolen 
glove or mitten as an aid in maintaining his hold. He kills the fish 
by a blow on the head wdth a club and, casting it on the trap floor, 
repeats the operation until from 40 to 50 have been killed. At some 
stations it is customary to cut off the tails at the base of the caudal 



U. S. B. F.— Doc. 879, 



Plate VI 




U. S. B. F.— Doc. 879. 



Plate VIII. 




FERTILIZING EGGS OF CHINOOK SALMON. BIG WHITE SALMON (WASH.) 

STATION. 



ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 19 

with a broadax, so that the fish may bleed freely. While this is not 
absolutely essential, it prevents the eggs from coming in contact 
with a large quantity of blood. The fish are washed by dashing 
water over them, the blood escaping through the open floor. 

Male fish are then thrown out from their pen and left long enough 
to undergo the exhaustion necessary to permit their being handled 
without much difficulty. 

The spawn taker uses a " straight-jacket," as it is called, merely 
'for the convenience of holding the fish. This is a sort of trough 
made the average length of a salmon and hollowed out to fit its gen- 
eral shape. A female is picked up by the gills and placed in this 
device. With a sharp, short-bladed knife the spawn taker makes an 
incision from the vent through the thin abdominal wall along 
the side, and the eggs flow out into a spawning pan or bucket held 
by another attendant. This is iimnediately passed to a third man, 
while a fourth man picks up a male fish. Grasping the tail of the 
fish with his left hand, and thrusting its head under his right arm, 
or in the case of a larger fish, between the knees, with his right hand 
he presses the milt out upon the eggs as soon as possible after they are 
taken. The eggs and milt are then thoroughly mixed by stirring 
with the hand. After being allowed to stand for a few minutes the 
milt is washed off, and the eggs are transferred to buckets and car- 
ried to the hatchery. Here they remain undisturbed until they have 
become water hardened and separate, when they are measured into 
egg baskets. The male fish is returned to the stream for use in fu- 
ture spawning operations. 

Blueback salmon in Alaska begin to leave the lakes in late August 
and September and ascend the streams to their headwaters to spawn. 
At suitable places near the mouths of such streams the fish are inter- 
cepted by racks, and seining operations are conducted in the waters 
below. The seine used, which is about 300 feet long, is loaded on 
a boat at a point below the rack, and, one end being held on shore, the 
remainder is distributed to posts projecting from the rack to the far- 
ther side of the stream. From here the boat continues downstream 
in a long sweep until the seine is played out to form a semicircle. 
The end last played out is operated by a man in waders, while the 
boat with the lead rope continues on to the starting point on the shore. 
At a given signal men stationed along the rack release the seine and 
follow it as it is hauled toward the shore, the two ends being brought 
together so as to completely envelop the fish, which are gradually 
worked toward the center. The seine is then stretched or hung on 
horses or tripods, and men equipped with woolen gloves grasp the 
corralled fish by the tail, segregate the sexes, and distribute them in 
boxes conveniently placed for the purpose. These boxes, supported 
on legs about 3 feet long, are made of three-fourths-inch lumber and 
divided by partitions into from 8 to 10 cells, each of them large 
enough to hold a fish placed in it head foremost, leaving about 6 
inches of the tail protruding. 

An operator stands at a box in which females have been placed and 
assorts them to determine as to their spawning condition, placing the 
ripe ones in another box and throwing the unripe ones back into the 
stream. A second man stands at the box containing the ripe fish and 
removes them one by one, killing them by a blow on the head with 
a club. They are then placed on a spawning table having a top 2 by 



20 ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

10 feet, in dimensions, 6-incli sides, and legs about 3 feet long, with a 
slope toward the operator at the other end. Across the table, for 
convenience in taking the eggs, is placed a small platform or bridge 
1 foot in width, with a slope of about 30° toward the upper end of 
the table, the face of which is studded with sharp-pointed nails one- 
half inch long to hold the fish in place. 

The spawn taker removes a fish from the table and places it on 
the platform with the head toward him, his left hand resting near 
the middle of its back. With his right hand he rips open the ab- 
domen from a point between the pectoral fins to the egg vent by 
means of a sharp-bladed knife, having a guard which permits the 
blade to project three-fourths of an inch. If the eggs are ripe they 
are easily removed by slightly inclining the fish toward the lower 
side of the board, where they gently fall into a pan placed to re- 
ceive them. The dead fish is then thrown aside and the operation 
repeated. After two females have been spawned a man at the op- 
posite side of the table removes the pan, replaces it with an empty 
one, which has first been moistened with water, and passes the pan 
of eggs to the operator handling the male fish, to be fertilized. After 
fertilization has been accomplished, the eggs are turned into a wash- 
ing box and held in a quiet current in the stream to clean up. This 
box somewhat resembles a corn popper in its construction, being 
made of fine-meshed wire and provided with a long handle and a 
hinged cover, with a clasp to hold it in position. Iii its bottom is 
a small trapdoor, operated by a lever near the end of the handle. 
After remaining in the stream a few minutes the eggs are emptied 
through the trapdoor into a bucket submerged about a foot under 
the surface of the water. Here they are held for half an hour to 
harden and are then carried to the hatchery, measured, and dis- 
tributed in standard salmon-hatching baskets, 50,000 being j^laced 
to a basket. 

HATCHING APPARATUS AND METHODS. 

The hatching apparatus usually employed is the so-called stand- 
ard salmon trough, with wire-cloth baskets. The troughs, which are 
generally constructed of cedar and redwood from 1| to 2 inches, 
dressed, are 16 feet long, outside measure, and 14 by 6| inches, inside 
measure. They are arranged in pairs, two or three pairs being 
placed end to end on different levels, with a fall of about 6 inches 
between each pair. 

Metal partitions divide each trough into compartments just 
enough longer than the baskets to permit of their being raised and 
lowered and subjected to slight tilting. The essential feature of this 
trough is the perfection of water circulation attained by means of 
cross partitions or riffle dams inserted at either end of each compart- 
ment. These partitions are made of No. 20 galvanized sheet iron 
and are held in place by saw scarfs in the sides and bottom of the 
trough. 

The first riffle dam is placed 7| inches from the head end of the 
trough, reaches entirely across, and extends from the bottom to 
within about H inches of the top. Two inches below this point 
a similar dam extends across the trough, reaching from the top to 
within 1| inches of the bottom. Twenty-six inches farther down 
similar dams are arranged, and so on throughout the entire length of 



AETIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



21 




22 ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

the trough, with the exception of the space between the second and 
third and the fourth and fifth compartments. Here the dams are 
placed 2f inches apart for the accommodation of iron braces, which 
prevent the troughs from bulging. Only one dam is used at the 
foot of the trough. This reaches across and extends from the bot- 
tom to within 1| inches of the top. In the center of the space at the 
foot of the trough is a 2-inch outlet, provided with a hollow cedar 
or metal plug, placed at the proper height. The water is thus forced 
to flow under the upper dam upward through the basket of eggs, and 
thence over the lower dam, etc. The troughs are provided with can- 
vas covers stretched upon light frames and made sunproof by satura- 
tion with asphaltum varnish, which is also thickly applied to the 
interior surface. 

The egg receptacles are oblong-mesh wire-cloth baskets about 13| 
inches wide, 24 inches long, and from 5^ to 6 inches deep, thus allow- 
ing them to project an inch or two above the surface of the water 
in the troughs. When wooden-rimmed baskets are used, the rim rests 
on the top of the trough and holds the basket 1 inch from the bottom. 
Arranged in this way the water passes imder the riffle dam at the 
head of the compartment, beneath the basket, and then upward 
through the eggs. The metal rim, which has been adopted in recent 
years, is supported by metal lugs fastened to the edge of the basket, 
rests on the top of the trough, and holds the basket in the same posi- 
tion as the wooden rim. In both cases the basket, when in operation, 
should be kept flush against the lower riffle dam of the compart- 
ment in which it is placed, to force the ascent of the water through 
the eggs. 

The number of eggs that can be incubated in a basket depends 
upon the species of salmon and the volume of the water supply. 
This varies with the chinook from 20,000 to 30,000; blueback, from 
50,000 to 60,000; silver, from 30,000 to 35,000; humpback, from 40,000 
to 50,000; and chum, from 33,000 to 38,000. 

The eggs suffer no injury from being in numerous layers, as water 
is constantly forced through the mass, partially removing the pres- 
sure. The baskets are constructed of galvanized wire containing 
from four to six meshes per inch, three-fourths of an inch long, the 
size of the mesh varying with the size of the eggs to be handled. The 
oblong mesh permits the fry to pass through onto the bottom of the 
troughs when hatched, but it is not large enough for the passage 
of the eggs. The advantages of this apparatus are: (1) The top 
of the basket is above water, so that the eggs can not overrun or 
escape; (2) by tilting one end of the basket a little, or by lifting it 
and settling it back gently in place, the bad eggs are forced to the 
top and can be easily removed with the ordinary egg picker; (3) 
space is consented, as the basket provides many times the number of 
eggs that could be accommodated on trays with an equal volume of 
water, the proper flow per trough being from 10 to 15 gallons per 
minute; (4) the ease and facility with which the mud can be dis- 
carded make it possible to remove all sediment collecting on the 
eggs by gently moving the basket up and down in the water several 

The period of incubation of salmon eggs depends upon the water 
temperature. A very safe rule to follow is one originally formu- 
lated bv Seth Green: 



AETinCIAL PROPAGATION OF PACIFIC SALMONS. 23 

In a teuiperature of 50° F. the eggs will hatch in 50 days. Every additional 
degree of warmth lessens the incubation period by 5 days, and every degree 
lower than 50 prolongs it 5 days. 

Salmon eggs are very hardy during the first few days, and while 
in this condition they are thoroughly gone over for the removal of 
the dead ones. At some stations it is customary after doing this to 
cover the eggs and leave them undisturbed until the spinal column 
is well formed, when the delicate stage has passed. This is not ab- 
solutely necessary, however, where skilled operators are employed. 
Men experienced in the work can handle the eggs throughout the en- 
tire period of incubation, and this is the most efficient method to pur- 
sue. When the number of unimpregnated eggs is great enough to 
w^arrant, they may be most advantageously removed by means of a 
salt solution, which should be applied only after the spinal column 
is well formed. 

By means of this solution, w^hich should consist of one part salt 
to nine parts of water, one is able to distinguish dead or unfertilized 
eggs at an early stage of development. The solution is held in a 
water-tight box or trough of 1-inch lumber, 40 inches long, 18 inches 
wide, and 12 inches deep. Inside of it is a second box of one-half 
inch lumber 3 inches less in width, 3 inches deeper, and provided 
with handles and a screen bottom. The dead eggs are removed with 
a net or scoop made of basket wire. The trough or outer box is filled 
to within a few inches of the top with water, and salt is added grad- 
ually and dissolved until the proper density is attained, this being 
determined by testing a few good and bad eggs in a small portion 
of the solution each time salt is added. This has been demonstrated 
to be a more satisfactory method than weighing or measuring, as salt 
readily absorbs- moisture and varies in purity. 

The box with the screen bottom is placed in the solution, wedged 
down, and a full basket of from 35,000 to 60,000 eggs poured into it. 
In less than one minute the good eggs will settle to the bottom, and 
the bad ones can be removed with the wire scoop. The inner box 
can then be lifted out and the good eggs returned to the basket and 
to fresh water, the whole process not requiring over three minutes. 
One solution can be used over and over again by adding sufficient salt 
to maintain a uniform density. 

The box or trough was adopted because of convenience in handling 
and because it furnished the necessary amount of surface, a very 
important feature to consider, as the bad eggs, if crowded, would 
cause the good ones to float by mingiingi with them. Quite an ex- 
tensive use of this method of cleaning the eggs has shown no delete- 
rious results, and where there are over a thousand dead eggs in the 
basket at the time the empties are turned, the use of the solution will 
effect a saving of labor. 

PACKING SALMON EGGS FOR SHIPMENT. 

Cases made of 1-inch lumber and of suitable size for packing on 
horses or mules are used for moving eyed salmon eggs over rough 
mountain trails from the collecting fiekls. The bottom of the case 
is lined with a thick layer of moss and covered with a piece of mos- 
quito netting. On this a layer of eggs is spread and covered with 
netting. Successive layers of moss, netting, and eggs are thus ar- 
ranged up to the middle line of the case, where a firm wooden parti- 



24 



ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 



tion is fastened on. The packing is then resumed as before until the 
case is filled, when the cover is screwed on, and the eggs are ready to 
be transported. 

For shipping eyed salmon eggs to various points in the United 
States what is known as the Atkins-Dinsmore case has been quite 
generally substituted for the old tray-shipment method described on 
page 84 of the Appendix to the Annual Report of the U. S. Com- 
missioner of Fisheries for 1897. Eggs can be transported in the 
Atkins-Dinsmore case as soon as the eye spot is plainly visible and up 
to within a few weeks of hatching. When shipped at too late a period 
of development, however, the eggs will hatch en route and the em- 
bryos perish. 

This method of packing eggs * * * jias the special advantage of making 
a comparatively light package — a factor of great economic importance in trans- 
portation. The outside case may be an ordinary box of suitable dimensions. 



.zy^.r 



% 

^ 



•bv 



-^ 



Vh 



'^ 



\ 



A 




V 






V 

I 

.X 



i?:: 



Fig. 7. — Atkins-Dinsmore shipping case. Plan. 

In it are packed, surrounded by moss, several boxes made of three-eighths-inch 
boards, and usually 12 inches wide by 1.5 inches long by 3i inches deep, each 
box containing a mass of 10,000 to 20,000 eggs in mosquito netting, with moss 
around all sides. No ice is used, care being taken that the packing be done 
in a temperature below 50°, that all packing material be kept in a place 
slightlv below freezing point, and that the moss in which the eggs are packed 
be sprinkled with snow. This method of packing is an economical one for 
shipments of eggs of Salmonidse during cold weather, but can not advanta- 
geously be used for eggs of spring-spawning fishes unless there is available a 
cold-storage room in which to do the packing. Recently the superintendent of 
the Baker Lake (Wash.) station, who has had occasion to ship eggs of steel- 
head trout and Pacific salmon in warm weather, has packed them in light 
cases with alternate layers of moss, and then placed two tiers of these thin 
cases side by side in an outer case with a large hopper of ice over the whole, 
the drip passing down between the two tiers of inner cases. The chief ad- 
vantage of this case for long-distance shipments is in the fact that less ice 
is required than in other forms of cases using ice, with a consequent saving 
in transportation charges. It can also be used in warm as well as cold weather.« 

« Titcomb, John W. Loc. cit., pp. 743. 



ARTIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



25 



Wliile the methods described above have been successfully em- 
ployed in the transportation of eggs across the United States and 




Fig. 8. — Atkins-Dinsmore shipping case. Longitudinal section. 



44»^ t 



£? 


















"T 



4 



k 



<?/ 



Mtrfyj/ Sfr/p 



^s 



7/'<7. 






13 N 



"X 



KVt 



ft), 



0.7->' 



^^■-i*/<f 



xc 



•^ 1 . T - ^.^ai/er o/Mass 












3/r//T^e5 



Fig. 9. — Atliins-Dinsmore shipping case. Cross section. 

also to Europe without an attendant, shipments of eggs to points 
south of the Equator, usually leaving this country in winter and 
arriving at their destination in summer, have called for more than 



26 



AKTinCIAL PROPAGATION OF PACIFIC SALMONS. 



usiial attention to the methods of packing them, and a caretaker is 
quite essentiah 

_ The Argentine shipping case, successfully used under such condi- 
tions, has been described by John W. Titcomb as follows : « 



fS'<i'/oY "'o^-^ ^/ro^ff 







A highly efficient form of shipping case has been developed during the past 
few years for the transportation of eggs of the Salnionidre from this country 
to Argentina. This case is 3 feet 6 inches long, 2 feet wide, and not exceeding 
30 inches high, outside measurement, and is constructed of selected tongued 
and grooved lumber. It has double walls, with bottom and top common to 



« Titcomb, John W. Loc. cit., pp. 747-749. 



AETIFICIAL, PROPAGATION OF PACIFIC SALMONS. 



27 



both, the 2-inch space between the walls being filled with nonconducting mate- 
rial, preferably tightly packed shavings. Between the inner wall and the 
stack of trays is a 2f-inch space for ice, separated from the trays by perfo- 
rated zinc. Between the latter and the trays, in a three-fourths-inch space, 
are the vertical supports of the zinc, viz, double corner supports, one being one- 
half by I5 inches, the other being one-half by 1 inch ; two intermediate sup- 
ports of one-half by 1 inch material, which are provided on either side of the 
case and one at each end; and crass braces of one-half by 1 inch material, 
which extend from the uprights to the inner walls of the case. 

The ice hopper, 3 inches in depth, and having the same outside dimensions 
as the trays, rests upon the latter and fills the space between the uppermost 
tray and the top of the case. It has a perforated zinc bottom, and, to facili- 
tate handling, cleats of small ropes are attached to it. The top of the case is 
insulated with a 2-inch thickness of nonconductor covered with sheet zinc, this 
insulation fitting closely into the chest when closed, and thus covering not 
only the ice hopper, but the ice spaces around the sides as well. In the bot- 
tom grooves lead to a three-fourths-inch drain hole, which is provided with a 




Fig. 11. — Argentine shipping case. Section. 

cork. Two cleats seven-eighths by 3 inches are attached- lengthwise to the 
bottom on the outside. 

The trays are one-half inch deep, 27 inches long, and 9 inches wide, inside 
measurement, the frames being of one-half by one-fourth inch material. The 
bottom of each tray is covered with wire cloth. No. 25 gauge, about 12 meshes 
to the inch, stretched tightly to prevent sagging and consequent imeven dis- 
tribution of the drip water. A narrow binding of cloth is tacked around the 
bottom of each tray to prevent the wire edge from catching on the mosquito- 
net covering of the tray beneath. On the inside ends of the trays are fastened 
short lifting cleats, and wedges liold the trays securely in place. The bottom 
tray rests on three oue-half-inch cleats extending lengthwise of the case, one 
at either side and the other in the middle. It is important to have the trays of 
uniform size tliat they may be interchangeable. 

The trays and interior of the case are coated with asphaltum. To facilitate 
opening from either side, four hasps are used, two on each side of the case. 
Two rope handles side by side are placed on each end of the case, with a 
cleat of three-fourths-inch material just above the holes for each handle. 

Eggs selected for shipping should barely show the eyespots without the aid 
of a glass. In packing, a layer of damp moss is spread one-fourth of an 
inch deep as evenly as possible over the tray bottom, and upon this is placed 
a covering of mosquito net or bobbinet. The eggs are laid upon the netting 
one or two layers deep, spread to within one-half inch of the tray frame, and 
covered with another piece of netting to keep them separate from the moss, 
which is sprinkled in a light layer over it, filling the tray. The netting is cut 
large enough to extend over the outer edges of the tray, so that the eggs may not 
be disturbed wlien a tray is lifted for examination. 



28 AKTIFICIAL PROPAGATION OF PACIFIC SALMONS. 

On shipboard, as the greater part of the journey is made, the cases of eggs 
are liept in one of tlie fruit or cold-storage rooms having a temperature of about 
38° F. To this room the attendant has access, and it is his duty daily to 
moisten the eggs by pouring through the ice hopper water of the same tem- 
perature as the eggs, 34° to 35°. The ice compartments are frequently re- 
plenished, and the eggs are picked over whenever necessary. 

It will be seen that the method of caring for the eggs is not novel. The 
chief improvements in the case are to make it easy for the caretaker to handle 
the eggs in the crowded quarters of a ship's storage compartments and to 
facilitate handling each individual tray. \ 

WATER SUPPLY TOR HATCHERY. 

One of the most important factors to be considered in connection 
with sahnon propagation is the water supply, which should always 
be taken from a stream that salmon are known to frequent for spawn- 
ing. Spring water or water from a spring-fed creek is objection- 
able, as it shortens the incubation period, bringing out the fry at 
an earlier period than if hatched under natural conditions and at 
a season of the year when the natural food supply in the streams is 
at its lowest ebb. 

In choosing a site for a salmon hatchery the matter of conveying 
water thereto at a proper height for a gravity service should be 
planned for, if possible. The supply may be conducted through a 
substantially built flmiie or by a pipe line, the dimensions of either 
to be governed by the extent of the work contemplated, having in 
mind th-e further development of the plant and the size of the pond 
system it is desired to establish. The point for the intake should be 
selected with the view to its protection, so far as is possible, from 
the ravages of floods and ice. This may be accomplished by means 
of piling or sheer booms. In some cases the construction of a low 
dam will be required in order to raise the water to the proper level 
to enter the flume or pipe line. 

Water taken from an open stream always contains more or less 
sediment, necessitating the use of a filter for the elimination of the 
greater part of it. A small quantity of sediment in the water supply 
is not objectionable; in fact, it is apparently beneficial. 

Where a proper fall can be secured, with a sufficiently rapid cur- 
rent at the point of intake, the water can be delivered by means of a 
current wheel, provided climatic conditions are favorable to its 
operation. A wheel for this purpose should be constructed on the 
order of a large undershot water wheel, with buckets on the outside 
of the rim. As the wheel revolves the buckets fill and empty into a 
trough or tank connecting with the supply flume leading to the 
hatchery. 

CARE OF THE FRY. 

The eggs of the chinook salmon, as do those of the other Salmonidse, 
hatch very gradually at first, only a small percentage coming out the 
first day. But the number increases daily until the climax is reached, 
when large numbers of young burst their shells in a single day. 
Great care and vigilance are required at this time. The vast numbers 
of shells rapidly clog up the guard screens at the outlets of the 
troughs, which should be kept as free as possible by thorough cleans- 
ing from time to time. 



U. S. B. F.— Doc. 879. 



PLATE IX. 




FIG. 1.— HATCHERY AND FEEDING PONDS, DUCKABUSH (WASH.) STATION. 




FIG. 2.— CURRENT WHEEL, HORNBROOK STATION, KLAMATH RIVER. CALIF. 



ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 29 

After nil the eggs are hatched and the baskets and riffle dams are 
removed from the troughs, each trough is divided into three equal 
compartments for holding a certain proportion of fry by inserting 
in the saw scarfs which carry the riffle dams 7 by 141 inch screens, 
made of No. 9 gauge zinc. The size of the perforations, which are 
horizontal in shape, should be governed by the species handled, and 
the four outer edges of each screen should have a one-half inch mar- 
gin of unperforated metal. The number of fry that can be held until 
the absorption of the yolk sacs ranges from 30,000 to 50,000 per 
trough, varying with the species and the water supply available. 

In the deep trays the newly-hatched fish are mixed with unhatched 
eggs, and the advantage of the oblong mesh in the bottom of the 
trays becomes apparent. This mesh is too narrow to allow the eggs 
to fall through, but the hatched fish, being comparatively long and 
narrow, easily slip through the long meshes into the space below. 
They should be assisted by gently raising and lowering the tray at 
intervals, taking care not to raise them out of the water, as at this 
tender age a slight pressure against the wire of the tray will often 
produce fatal injuries. On this account too much caution can not 
be exercised in regard to handling them out of water during the first 
stages of the yolk-sac period, for the injuries can not be seen at first, 
and often the death of the fry is the first warning that they have been 
injured. 

After the eggs are all hatched and the young fish are safely out of 
the trays and on the bottom of the troughs, their dangers are few, 
and they require comparatively little care. Almost the only thing 
to be guarded against at this period is suffocation. Even where 
there is an abundance of water and room, with a good circulation, 
they often crowd together in heaps, or dig down under one another 
until some of them die from want of running water, which is not an 
inch away from them. The best remedy in such a case is to thin 
them out. 

FEEDING THE FRY. 

In recent years it has become well recognized that real success in the 
propagation of the Pacific salmons is determined in large measure 
by the extent to which the young are reared to the fingerling stage 
before liberating. The former practice of planting defenseless fry 
in wholesale numbers a short time before the final absorption of the 
yolk sac is now almost obsolete. This pertains particularly to the 
blueback and silver salmons and in less degree to the chinook, for 
these are known to pass a part or the whole of their first year's exis- 
tence in fresh water, a period of residence that has been determined 
conclusively, chiefly as the result of general investigations and study 
of salmon scales conducted in recent years by Dr. C. H. Gilbert, of 
Stanford University, Calif. 

The demand for fingerlings which has naturally followed this 
recognition of the great value of fingerlings over fry has developed 
the necessity for a cheap food, one that will furnish proper nourish- 
ment for the young fish and be available in large quantities, as the 
cost of liver, which has long been a favorite article of food for young 
fish on the west coast, has become prohibitive, except for occasional 
use and to afford a change of diet for a short period. 



30 AKTIFICIAL PROPAGATION OF PAClf'IC SALMONS. 

One of the first cheap foods to be utilized in large quantities by the 
Bureau of Fisheries was the Columbia River smelt, which was first 
tried at the Oregon stations about five years ago. These fish can be 
purchased during the run at the height of the season for $20 per ton 
at a cold-storage plant in Portland, Oreg. An additional charge of 
$20 per ton covers sharp freezing and storing for a period of six 
months, and this, together with transportation charges, makes the 
average cost of the fish about 2^ cents a pound delivered. 

Smelt have l>een fed both raw and cooked. When used in the 
raw state the fins and heads are removed, and the fish are ground once 
through the coarse plate of an Enterprise meat chopper, after which 
they are run through the fine plate twice. However, this method has 
not proved very satisfactory, as smelt are very oily, and, in feeding, 
difficulty has been experienced in keeping the troughs clean. Intes- 
tinal trouble is also feared from the innumerable small, sharp bones. 

The method which has given most satisfactory results is to place 
the smelt in 50 or 100 pound lots in a farm kettle and cook them 
until the bones become softened. After this a quantity of the 
cooked mass convenient for handling is placed in gunny sacks and 
permitted to drain thoroughly. The mass in the sack is then trans- 
ferred to a press of convenient size, operated by an ordinary house 
jack, and is pressed into cakes 12 inches square and varying from 3^ 
to 4 inches in thickness. The burlap forming the sack is peeled 
away and is serviceable for further use. Quantities of this food can 
be prepared at one time, and, if kept in a cool, dry place, will remain 
in a wholesome condition for several days. When needed for food 
it is grated by means of a homemade power grater and screen, the 
degree of fineness depending upon the age of the fish to be fed. 
After this operation it presents the appearance of coarse meal. It 
can be scattered over the surface of the water and is cleaned up by 
the fish before it reaches the bottom. Prepared in this manner it 
makes a good, clean, rich food, and the fish take it readily. Its cost 
is also very moderate. 

Beef and hog melts have been successfully used in conjunction with 
mush, both for the purpose of varying the diet, and with the view of 
eliminating the use of liver in large amounts after the fish are a few 
weeks old. The cost of this material will average about 3 cents per 
pound. 

Culled canned salmon, or " do overs," have also been employed to 
good advantage in the feeding of young salmon. The contents of 
the cans are first thoroughly heated and then pressed and grated 
in the manner described above in the preparation of smelt. Par- 
ticular attention is invited to this method of using canned salmon 
as fish food in view of the fact that considerable complaint has been 
made as to the results of its use in the past. If prepared in the 
manner specified, the material is certain to give satisfactory results. 

After several years' success in the feeding of canned salmon it 
occurred to representatives of the Bureau that the fish used in a 
spawning operation, if properly preserved and prepared, would 
make a good and inexpensive food. Instructions were accordingly 
issued to all the west coast superintendents, including those in 
Alaska, to put up a quantity of the spawned salmon, and it is ex- 
tensively used at those stations at the present time. After being 
relieved of their eggs the fish are skinned, sj^lit, and carefully boned. 



ARTIFICIAL, PROPAGATION OF PACIFIC SALMONS. 31 

They are then placed in tanks or barrels, with alternate layers of 
salt, water being added in sufficient amount to keep the brine well 
over the top layer. 

The material has also been prepared by dry salting in dairy salt 
and packing it in a dry, tight box or other container, weighing it 
down in a solid mass. The fish are then taken out, rinsed in fresh 
water, and hung over a pole in the dry house. A slow heat is applied 
at first to toughen the fiber, following which they are kept in the 
dry house until quite hard and dry, when they are packed in boxes 
between layers of papers to absorb any moisture and held in a dry 
storage until needed. 

Still another method was tried at the Bureau's California stations, 
where a quantity of sundried or sun-cured salmon was prepared with- 
out salt, the climatic conditions being favorable for curing salmon 
in that manner until late in the fall. 

Several methods of preparing this food were adopted. In all 
cases, however, the fish were first soaked well, preferably overnight, 
in running water, to remove the salt. Some were then cooked, 
pressed, and grated ; others were prepared by grinding in an Enter- 
prise meat chopper and mixing the meat with a mush made from 
middlings. Quantities have also been prepared and fed in the raw 
state. In all forms the material has proved excellent, and when 
used in conjunction with small quantities of liver or plucks, to vary 
the diet, the results have been eminently satisfactory. Its cost, based 
on the lots M'hich have so far been put up, has averaged 1 cent a 
pound. When prepared in large quantities, it should be materially 
cheaper. 

Most excellent results were attained with this food at one of 
the Puget Sound stations of the Bureau of Fisheries. In a slough 
where several hundred thousand fish had been placed at the time 
of the absorption of the yolk sac, sides of salted salmon were laid 
on the bottom. As the meat softened, hundreds of young fish 
could be seen working on it, and it was finally all devoured. The 
fish remained in the slough under the care and observation of an 
attendant, attained a rapid growth, and developed into splendid 
fingerlings. 

Under such an arrangement the expense of salmon rearing is 
reduced to a minimum, and work of similar character should be 
encouraged on all salmon streams where the natural conditions are 
favorable. 

In connection with rearing operations the importance of providing 
a mixed diet can not be too strongly emphasized. If the principal 
food consists of the prepared fish, a food of liver and mush should be 
given frequently. Wliere this is done as often as once a day, it will 
be found to produce the most rapid growth. No matter how good 
any one food may be, nor how cheaply it is prepared, the best possible 
results will be attained where a variety is used. 

PLANTING YOUNG SALMON. 

Wlien the salmon have reached the proper age for distribution, 
they should be released on or near the natural spawning grounds, in 
the most protected spot that can be found. It is unwise to liberate 
young salmon before they have absorbed the yolk sac, and where the 



32 ARTIFICIAL PROPAGATION OP PACIFIC SALMONS. 

necessary facilities exist it is advisable to feed them until they have 
attained a length of at least 2^ inches, as fish of that size are much 
more likel}' than fry to elude their enemies. 

The following information bearing upon the ages at which salmon 
should be planted is taken from a report of Dr. C. H. Gilbert, Pro- 
fessor of Zoology, Stanford University, on investigations made by 
him for the U. S. Bureau of Fisheries and for the commissioner of 
fisheries of British Columbia : 

The bliieback spawns normally either in its fourth or fifth year, the chinook 
salmon in its fourth, fifth, sixth, or seventh year, the females of both species 
being preponderatingly four-year fish.<^ 

The young of both blueback and cliinook salmon may migrate seaward 
shortly after hatching, or may reside in fresh water until their second spring. 
Those of the first type grow more rapidly than the second, but are subject to 
greater dangers and develop proportionately fewer adults." 

[In the case of the blueback salmon] examination of scales from all the 
important blueback streams of the Province has shown for each basin that 
adult fish are derived from yearling migrants, to the practical exclusion of 
those which migrate as fry. Out of some 8,000 bluebacks of the 1913 run, 
only 12 fish seemed with some probability to have developed from fry migrants. 
It would seem, then, that with few exceptions the fry of this species perish 
after entering the sea. The only alternative to this conclusion is that fry 
develop in the sea in precisely the same manner, at the same rate, and with 
all the local peculiarities marking those of their own basin, which develop for 
a year in their native lake. To one acquainted with all the facts, such an 
hypothesis appears impossible and absurd.* 

The deplorable waste occasioned by the loss of vast numbers of fry can not 
be checked, it would seem, in the case of such progeny as are the result of 
natural spawning. They can not be held back from migrating as fry if the 
instinct seizes them. But the case is different in hatchery practice. Here 
[British Columbia] it is still the custom to release the young as soon as the 
egg sac is absorbed and free feeding begins. But, in view of the conditions 
here pointed out, it would appear to be imperative that the fry of the year 
hereafter should be held in troughs or ponds and fed until midsummer, when 
the time for downward migration will have passed. They can then be deposited 
in the lake, with full confidence that they will pass to sea as yearlings the 
following spring.* 

Silver salmon spawn normally only in their third year. The young migrate 
either as fry or yearlings, but adults are developed almost exclusively from 
those which migrate as yearlings.® 

Chum salmon mature normally either in their third, fourth, or fifth year; 
humpback salmon always in their second year. The young of both species pass 
to sea as soon as they are free swimming.'^ 

The term " grilse " as used for Pacific salmon signifies conspicuously undersized 
fish which sparingly accompany the spawning run. They are precociously 
developed in advance of the normal spawning period of the species. So far as 
known, the grilse of the chinook, silver, and chum salmons are exclusively 
males, of the blueback, almost exclusively males, except on the Columbia 
River, where both sexes are about equally represented. The larger grilse meet 
or overlap in size the smaller of those individuals which mature one year later 
at the normal period.* 

The great differences in size among individuals of a species observed in the 
spawning run are closely correlated with age, the younger fish averaging con- 
stantly smaller than those 1 year older, though the curves of the two may 
overlap.® 

» Gilbert, C. 11.: Age at maturity of the Taciflc coast salmon of the genua Oncorhyn- 
chus. Bulletin, U. S. Bureau of Fisheries, Vol. XXXII, for 1912, pp. 21-22. Washington, 
1913. 

" Gilbert, C. H. : Summary of Contributions to the life-history of the sockeye salmon. 
(No. 1.) British Columbia. Report, Commissioner of Fisheries, for 1913. pp. RlO-Rll. 
Victoria, 1914. 

o 



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